Flavor Perception in Normal, Healthy Adults
Conditions
Brief summary
Ketone ester (KE) drinks are sold commercially in the USA and elsewhere (the FDA has accepted a GRAS (generally regarded as safe) notification on the KEs we propose to study). KE drinks can have beneficial effects on metabolism. Unfortunately, KE drinks have a strongly unpleasant flavor which can trigger rejection. The current study will generate data to help inform KE drink formulations with improved flavor. First stage, trained subjects will rate the intensity of various sensation qualities (e.g., bitter, sour, metallic, and astringent) from KE drinks to help understand the nature of the unpleasant flavor and the particular sensory systems involved (e.g., taste vs. smell). Then, subjects will taste KE drinks with and without various flavor modifiers. Subjects will be healthy adults (aged 21-45) without known food allergies.
Interventions
OTHERFlavor additive
Various flavor additives will be tested (vs. no added flavor) to determine which show promise for making KE drinks taste less unpleasant
Sponsors
HVMN (funding; holder of primary Department of Defense STTR contract)
Monell Chemical Senses Center
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
OTHER
Masking
NONE
Masking description
Samples presented will not be identified (there will be no codes or visual cues regarding whether a model drink does or does not contain a flavor modifier). However, true blinding is impossible since flavor will differ between samples. Investigators will not be blind to sample contents. However, responses will be collected and recorded using an automated computer program, which offers some protection against possible experimenter bias.
Intervention model description
Within-subjects design (the same group of subjects will taste model KE drinks with vs. without added flavors), with order counter-balanced.
Eligibility
Sex/Gender
ALL
Age
21 Years to 45 Years
Healthy volunteers
Yes
Inclusion criteria
1. Good general health (self report) 2. Men and women 3. Age from 21 to 45
Exclusion criteria
1. Current (or within the last four weeks) acute illness, such as cold or flu 2. Currently active allergies 3. Regular use of medication (over the counter or prescription), except for birth control. 4. Any history of food allergy or sensitivity (particularly to KE drinks or MSG). Any history of sensitivity to 6-Propylthiouracil (bitter compound frequently used to assess individual differences in sensitivity to bitterness). 5. Pregnant, nursing, or trying to become pregnant during the study (pregnancy can affect flavor perception) 6. Chronic illness (any ongoing condition that is serious or required medical monitoring), including kidney problems, liver problems, cardiovascular problems (e.g., heart disease or high blood pressure), diabetes, HIV infection, or other ongoing illness). Diabetes or other metabolic issues could be important for safety as well as quality of data. 7. History of taste problems (absent or abnormal sense of taste) 8. Weigh less than 100 pounds (45.4 kilograms). This is to help ensure that the amount of KE drink consumed remains below the single serving in the GRAS (generally regarded as safe) notice which the FDA has accepted.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Rated intensity profile | Through study completion (up to a year for a given participant, depending on how many drink samples the participant agrees to evaluate). Participants will rate the intensity of about 12 model drink samples during each study visit. | Rated intensity of taste qualities (e.g., sour, bitter) and mouth-feel (astringent) of model drinks, measured using the general Labeled Magnitude Scale (gLMS). In this implementation of the gLMS, scores will range from 0 (or no sensation) up to 100 (strongest imaginable sensation), with higher scores indicating stronger perceived intensity for the sensation in question. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Hedonic response | Through study completion (up to a year for a given participant, depending on how many drink samples the participant agrees to evaluate). Participants will rate the pleasantness of about 12 model drink samples during each study visit. | Ratings of how likely the flavor of each sample tasted would be to discourage use of a product with that flavor, assuming the rater otherwise wanted associated nutritional or performance benefits |
| Rated upper GI symptoms | Through study completion (up to a year for a given participant, depending on how many drink samples the participant agrees to evaluate). Participants will rate upper GI symptoms after tasting about 12 model drink samples during each study visit. | Rated intensity of nausea, bloating, and heartburn, using a nine-point category scale (some bitter liquids can trigger mild to moderate feelings of nausea). Scores for each symptom range from 0 (none) to 8 (Unbearable), with mild (2), moderate (4), and severe (6) as labeled intermediate categories. |
Countries
United States
Outcome results
None listed